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how close in sound can a tube and ss amp sound ?

i have observed threads requesting advice regarding tube sounding solid state amps, within a price point.

i wonder how to confirm such a request.

in addition to recommendations, what about comparing a particular ss amp to a particular tube amp using an experimental design where bias, or preconception has been eliminated ?

has anyone tested the hypothesis that he/she cannot detect the difference between a tube and a ss amp, within the same power range, price point and minimizing interaction problems, such as impedeance mismatches ?

on the other hand if someone is seeking a tube-like sound out of a solid state amp, i would assume that one would use a "classic" sounding tube amp, e.g., cj mv 45, cj 75, cj 100, or cj mv125 as the tube amp and try to find a ss amp that is indistinguishable from the sound of the classic tube amp.

i have found that many ss amps differ with respect to bass and treble response from many tube amps.

in my own case, i would love to find a 120 watt ss amp which sounds like my vtl tube amp. unfortunately, i am not optimistic.

in other threads, some people have stated that it is impossible to find a ss amp that is "tube-like", in the classic sense.
mrtennis
raquel
841 posts
 
Agreement. My Rowland Model 6's sounded, and my darTZeel sounds, quite similar to my VAC Renaissance amps, but not identical. There are strengths to each design.

I should also add that my darTZeel has not been retrofitted for the improved biasing circuit that is now available for it, so it's not being run optimally, and since we're doing comparisons, the Rowland, while excellent, is not the equal of the darTZeel.
wilsynet's avatar
wilsynet
264 posts
 
I don't think it's commonly agreed what a tube amplifier sounds like anyway. To say that you want a solid state amplifier to sound like a tube amplifier, well, what kind of tube amplifier and in what way?

In broad generalizations, an OTL does not sound like a SET does not sound like a Push Pull. Same with EL-34 versus EL-84, or 45 versus 2A3 versus 300B versus 845. Tube amplifiers are variously described as being euphonic, transparent, warm, extended, rolled off.

In my (albeit) limited experience, "dimensionality" and especially "fatigue free" seem to be hallmarks of what a (very) good tube amplifier will do that most solid state implementations find challenging without some other compromise.

Wilson
peterayer
1,382 posts
 
"Sounds like" or "sounds the same" are phrases often used interchangeably here, when in fact they are quite different. IME, the former is possible on very rare occasion while the latter is not, at least not yet.

I have owned many of the Class A Pass amps, both Aleph and X.5. From that perspective, on a few occasions when hearing a new system and not first looking at the components, I have been hard pressed to identify the type of amp playing.

I have heard very good SS and very good tube amps sound similar and pretty convincing. To answer the OP, I think they can sound fairly close, but not the same.
atmasphere's avatar
atmasphere
11,807 posts
 
The issue is going to be the distortion structure. Tubes in general favor the lower orders and depending on the amplifier technology can make a lot or a little of the even orders, usually with not a lot above the 5th.

(This is a general statement, for example our amps are fully-differential so there is no even-ordered harmonic at all until you approach clipping.)

Transistors for the most part are absent the lower orders. Instead they favor the odd orders and higher ones at that, usually the 5th, 7th and 9th. Now they do this only in trace amounts, but many tube amps don't make them at all.

The odd orders are heard as brightness and also makes the presentation seem louder.

The lower orders are heard as warmth, bloom, that sort of thing.

So either way you look at it, distortion is what we are trying to get rid of and as far as the tubes/transistor thing goes, its two ways of doing that with a different price. Fortunately topology plays a role too, so its not cut and dried- IMO the variations we see are what make the high end part of the industry so interesting.

mrtennis OP
3,295 posts
 
i appreciate the wisdom and experience imparted in the above posts, especially ralph's technical explanation as to why ss and tube amps should sound different.

human hearing is imperfect, so i ask the question again:

has anyone been unable to detect differences between a specific ss amp and a specific tube amp?

if so, what tube amp and what ss amp and under what (experimental) conditions ?
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